On this day…

In 1877, Thomas Edison invented the phonograph, a device used for the recording and reproduction of sound recordings. While it was originally stated that Edison had tested his invention on August 12, 1877, most historians believe it happened a few months later, as Edison didn’t file for a patent until December 24, 1877. Additionally, the diary of Charles Batchelor, one of Edison’s aides, confirms that the phonograph was not constructed until December 4, 1877. The patent on the phonograph was issued on February 19, 1878.

Thomas Edison’s phonograph was highly original. Other inventors at the time had been able to produce devices that could record sounds, but Edison’s phonograph was the first to be able to reproduce the recordings. French scientist Charles Cros mentioned a similar invention in a paper in on April 18, 1877. However, there were many differences and Cros’ model remained just a theory, as he did not produce a working model.

Thomas Edison’s phonograph was based on two of Edison’s previous works, the telegraph and the telephone. Edison was working on a machine that would repeatedly transmit telegraphic messages by devising a method for capturing a passage of Morse code as a sequence of indentations on paper. When he played the paper tape through the machine at a high speed, Edison noticed that the noise resembled spoken works. This prompted Edison to experiment with a stylus and tin foil wrapped around a cylinder. When Edison would speak into the mouthpiece, the sound vibrations would create indentations on the foil. Once the machine was created, Edison tested it by recording the nursery rhyme, “Mary had a little lamb.”